Organisation des Nations Unies pour l’alimentation et l’agriculture- FAO
Paiements des services environnementaux (PSE) dans les paysages agricoles
Que sont les services écosystémiques
La valeur des services écosystémiques
Estimating the value of ecosystem services is a difficult task. Option values, as well as bequest and existence values should be taken into account together with the use values....
For provisioning ecosystem services, such as the production of food or provision of water, market prices indicate their direct use value, because their products are bought and sold. But for many ecosystem services, market prices do not exist, therefore quantifying their importance or estimating their value is difficult.
The total economic value of an ecosystem service can be estimated from the different types of uses we draw from them - direct use, indirect use and the value of keeping the option open to use them later (see figure 1.2).
Figure 1.2 - The total economic value of ecosystems(8)
Direct use values are those drawn from provisioning services as marketed goods or services, whose market price indicates the value we put on their direct use. This applies to commodities like food, timber and water, but also to entrance fees to a protected area for education purposes, or salmon fishing licences for recreation in the countryside.
However, this consumable part of the ecosystems is only the tip of the iceberg. Underlying their production are regulating services that control water or air quality, and our use of them feels indirect. Yet they have a value that is reflected by, and can be estimated from how we behave as consumers. For example, although we might not pay for the maintenance of a healthy lake per se, we may be willing to pay a higher price for a house near such a lake or to drive longer to visit the especially pleasant landscape around this lake (indirect use value) (9).
Other more indirect values can still be traced in the benefit of preserving the possibility of future direct or indirect use. For example, investment in biodiversity conservation is often based in the option values of preserving ecosystem, species and genes for potential future use.
Furthermore, people may value ecosystem services without ever actually deriving any use value from them. Some of us may value the preservation of some environmental amenity for its existence value alone, or for knowing that an ecosystem will be conserved for future generations (bequest value).
As an example, the table 1.3 shows estimates of economic value of the various ecosystem services provided by watersheds.
Table 1.3 - Estimates of economic values of watershed ecosystems services (10)
It is in this context that Payments for Environmental Services (PES) (or PES schemes) have developed (as) incentives to help incorporate the indirect use and existence values into the products and services of ecosystems that are already bought and sold. On the one hand, these schemes encourage land managers to consider the impacts of their land use decisions on the regulating, cultural and supporting services of the ecosystems they manage. On the other, they highlight these underlying values of the goods and services that consumers use and secure a contribution for their protection and enhancement.
A simple example of how a payment scheme could work would be a city's water supply company collecting an extra charge on their water use fee, to be invested in the protection of the water regulation and purification services provided by the watershed that supplies their river with water. Schemes exactly like this hypothetical example are already happening all around the world. For more details on how these schemes work - see the next section on "What are Payment for Environmental Services (PES)".
(8)Smith, M., de Groot, D. and Bergkamp, G.2006. Pay - establishing payments for watershed services . Gland, Switzerland, IUCN - The World Conservation Union.
(9)These examples refer to the use of methods for valuation of indirect use values, such as hedonic pricing or travel cost.
(10)Smith, M., de Groot, D., Perrot-Maitre D. and Bergkamp, G.2006. Pay - establishing payments for watershed services . Gland, Switzerland, IUCN - The World Conservation Union.
